Combinação das técnicas de precipitação ácida e complexação para obtenção de frações enriquecidas de α-lactoalbumina e β-lactoglobulina do isolado protéico de soro de leite

• Autor(a) principal: Rocha, Roney Alves da
• Data de Publicação: 2008
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/2853
• topic: Soro de queijo; Precipitação; Alfa-lactoalbumina; Cheese whey; Precipitation; α-lactoalbumina; β-lactoglobulin; CNPQ::CIENCIAS AGRARIAS::CIENCIA E TECNOLOGIA DE ALIMENTOS::TECNOLOGIA DE ALIMENTOS

In this work it was studied the effects of the combination of two techniques for proteins recovering, in order to obtain an enriched fraction in α-lactalbumin and an enriched one in β-lactoglobulin, from commercial whey protein isolate (WPI) of cheese. The employed techniques were the acid precipitation and the complexation of calcium ion, present inside α-La. The used raw material was WPI of BiPRO® mark, produced and marketed by Davisco Food International Inc., USA. In the reconstituted whey five factors were investigated: pH, time of agitation, temperature of process, complexing type, and concentration of WPI. After addition of acid and centrifugation, were obtained two fractions: one fraction supernatant and a fraction of precipitate, that were submitted, individually, and for each treatment, to chromatographic analyses (HPLC), to evaluate the amount of α-La and β-Lg present in each one. For the precipitate, enriched in α- La, it was detected that the best conditions of protein recovering, with the imposed restriction of minimizing the co-precipitation of β-Lg, were: time of agitation of 30 minutes, process temperature of 40 °C pH 3.9, 12.0 % (w/w) for WPI concentration, and the use of citric acid as complexing. For the supernatant, enriched in β-Lg, it was detected that the best conditions of protein recovery, with the imposed restriction of minimizing co-recovering of α-La, were: agitation time of 30 minutes, process temperature of 30 °C, pH 3.9, 9 % (w/w) of WPI, and the use of lactic acid as acidifier, being able to, in it's substitution, another acidifier of smaller cost to be used. In addition to the analyses accomplished for the precipitate and for supernatant, was settled down a objective function that allowed to esteem, over the experimental conditions accomplished, a point of optimization. This point refers to values of levels of the factors in study whose recovery of α-La in the precipitate and the recovery of β-Lg in the supernatant are simultaneously maximized, while the co-recovery of α-La in the supernatant and the co-precipitation of β-Lg in precipitate are minimized. In these conditions the found values were: agitation time: 30 minutes, process temperature: 40 °C, pH adjusted for 3.9 with citric acid, concentration of WPI of 9 % (w/w), and addition of tribasic sodium citrate as the complexing agent.